The book is full of different types of puzzles split into separate weeks over a twenty-four week period - getting harder as the weeks progress. Some are more challenging than others depending on what the individual is good at, and what they are not - numbers/words/reasoning etc. I have come across some of the actual types of puzzles in other publications so am familiar with them - Killer Sudoku, Kakuro, Bridges for instance - which makes them easier for me, however there are all sorts of different 'brain games' and it's an enjoyable workout. Don't particularly like the 'Creativity' part that appears at the end of each week, but then I'm not very creative so I guess that's the challenge!!